Congenital heart disease (CHD) affects roughly 2 million people in the US and remains responsible for twice as many years of life lost as all of childhood cancer combined. Cardiac magnetic resonance (CMR) imaging has become the gold standard technique that clinicians use to monitor cardiovascular function in patients over time. Advanced CMR techniques offer incredible potential for improving our ability to diagnose and treat patients with CHD, but currently require long acquisition times that limit their feasibility n the clinic. Our overall goal is to make these advanced CMR techniques clinically feasible through dramatically reducing the time required to acquire the image data. We propose a new CMR system, which we call videogame interface for diaphragm location (VIDLoc), that can reduce acquisition times by 50%. VIDLoc works by advising children how to alter their breathing patterns in real-time, during CMR, in order to dramatically reduce the total time required to acquire CMR data. Because the heart moves up and down on the diaphragm as children breathe, imaging can only be performed when the diaphragm is within a narrow region called the acceptance window. Since children breathe very erratically, the amount of time they spend in the acceptance window is often as low as 20% (thus imaging can only be performed 1/5th of the time). VIDLoc overcomes this by imaging the child's diaphragm location in real-time and using this to generate a videogame showing a car on a road. The car's location relative to the road represents the diaphragm location relative to the acceptance window. VIDLoc will provide instructions to children to guide their diaphragm (or car) to be within the acceptance window (or road), where the heart can be imaged. We hypothesize that using VIDLoc will increase the amount of time spent in the acceptance window and therefore dramatically reduce CMR acquisition times. This will make advanced CMR techniques clinically feasible in patients with CHD. We will first optimize VIDLoc by adding extra features, such as text and voice feedback of breathing instructions, which will be tested by children with CHD to determine each feature's effectiveness. Then, we will test VIDLoc against conventional free breathing for acquisition time and quality of data derived. Twenty children with CHD will undergo an advanced CMR technique to image three-dimensional cardiac motion. Lastly, we will quantify the acquisition time and quality of data derived from VIDLoc with and without pre-CMR training in a simulator. A simulated version of the VIDLoc system outside of the scanner will use a sensor to quantify chest wall excursion as a proxy for diaphragm location. Twenty children with CHD will be randomized to undergo advanced CMR using VIDLoc with or without pre-CMR training in the simulator. Acquisition times and image quality will be used to determine the efficacy of pre-CMR training. The overall goal of this proposal is to use VIDLoc to reduce CMR acquisition time so that we can start using advanced CMR techniques in the clinic to ultimately improve the lives of patients with congenital heart disease.